It seems the OP has answered his own question. If you value the ability to finely control your bike, then rollers are invaluable as a training aid. Fine control is fundamental to everything on your list. Also, you left off your list pack riding, which seems relevant if you are looking to get into road racing. If you don't value the ability to finely control your bike, then rollers are a waste of time and money. Also, if you choose this path, be prepared to piss people off in a road race.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter